Steam valve



March 6, 1934.

K. S. M. DAVIDSON STEAM VALVE Filed July 13. 1929 KM M Patented Mar. 6,1934 PATENT OFFICE STEAM VALVE Kenneth S. M. Davidson, Newton Highlands,Mass., assignmto Crosby Steam Gage & Valve Ola-is Boston, Mass acorporation of Massachuse Application July 13, 1929, Serial No. 377,969

--s Claims. (01. 137-53) The present invention relates to safety valvesmore particularly employed for the relief of highpressure steam lines.

In valves of this character adapted to relieve steam pressures on theorder of 700 to 1200 pounds per square inch, it is important that thevalve on opening shall have a comparatively large capacity for'escapingsteam and shall be capable of continued operation with relatively slightvariation in operating characteristics. I have found that in valves ofthis type as previously constructed, continued operation with the hightemperatures at present employed tends to alter the pressure at whichthe valve opens, in certain cases a reduction of six to eight per cent.in popping pressure having occurred.

I have discovered that this undesirable variation in popping or openingpressure of the valve can be avoided by removing the valve loadingspring from the immediate vicinity of the escaping high temperaturesteam, and suitably preventing undue elevation of temperature of thespring through conduction of heat thereto. To this end I have elevatedthe loading spring well above and removed from the discharge port of thevalve, and have provided for radiation of heat away from the spring andminimized the conduction of heat thereto.

Still further features of my invention consist in novel features ofconstruction, combinations and arrangements of parts, hereinafterdescribed and claimed, the advantages of which will be obvious to thoseskilled in the art from the following description.

In the accompanying drawing illustrating the preferred form of theinvention,

. Fig. 1 represents a sectional elevation of the valve embodying theimproved features of my invention; and

Fig. 2 is a section upon the line 2-2 of Fig. 1.

In the valve shown in the illustrated embodiment of the invention, abody of cast steel is provided with an outlet nozzle portion 12, and aseparable throat tube 14 formed as a steel forging. The throat tube, asindicated, is integral throughout its entire length, and is threaded tothe cast steel body at 16. The upper edge or face of the throat tube 18forms the valve seat, and for this purpose cooperates with a forged diskvalve 20 having a raised rib or annulus 22 aligned with the seat. Thedisk normally moves within a guide sleeve or tube 24 mounted within theupper portion of the body 10. Control of relieving and blow-downpressures is accomplished by the ad justable seat ring 26 and shroudring 28, which are respectively threaded on the throat tube 14 and guidetube 24. Adjustment of the seat and shroud rings is maintained by virtueof threaded members 30 and 32 having innerends which engage slots 34 and36 in the rings. As will be indi- 60 cated, the shroud ring has aninwardly projecting lower portion 38 which serves to bring the activedeflecting portion of the ring into close proximity to the valve disk.In addition, the valve disk 20 is provided with a deflecting lip 40 atits outer 66 periphery. The disk is supported from the lower end of avalve stem 42 through the swivel connection indicated at 44. The mainportion of the stem 42 is surmounted by a reduced and elongated stem 45which extends upwardly within a loading 10 spring 46 mounted within anopen yoke or frame 48. The spring yoke is provided with an integral baseportion 50. and is connected to the body 10 through an intermediatespool frame 54. The spool frame comprises upper and lower head portions56 and 58 connected by vertical radial fins 60. The lower head portionis secured by bolts 62 to the top flange of the body, and the upper headportion is bolted to the skeleton bonnet by securing bolts 64. The stem,as indicated, extends upwardly through an opening 66 in the lower head58 amply large to provide clearance for the stem, and through alignedopenings 68 formed in the heads and 56 to prevent an undue volume ofsteam from passinginto the region immediately 95 surrounding the spring.To further prevent passage of steam upwardly around the stem, adefiector 70 is connected to the stem within the spool and above thestem opening 66 to deflect steam leaking through the openings upwardlybetween the radial fins 60. Heat conducted to the spool frame 54 fromthe body 10 of the valve is to a considerable extent radiated from thefins 60 through which air can circulate freely. Heat conducted along thestem 42 is also radiated from the stem by circulation of air thereaboutin the open region of the cooling spool through which the stem passes.By virtue of this construction, the temperature of the loading spring 46is not altered sufficiently to vary the operating characteristics of thespring. The construction of the cooling spool makes it feasible andpossible to modify existing valves of this general type by removing thespring frame from the body, lengthening the stem, and interposing thecooling spool between the spring frame and body.

The thrust of the loading spring 46 at the lower [end is resisted byahead 72 which rests upon by an adjustable abutment 76, the position ofwhich is varied to control the loading pressure of the spring by asleeve '78 threaded within the head of the spring yoke 48 and retainedin posion by a lock nut 80. The valve disk may be manually raised fromits seat in the usual manner through the provision of a lever 82fulcrumed at 84 in a bonnet 86 at the upper end of the spring yoke, thelever engaging a nut 88 connected to the upper end of the stem and beingoperated by a depending arm 90 fulcrumed on the arm side of the bonnetat 92, and adapted when moved outwardly to engage the outer end of thelever 82 to elevate the stem and valve against the pressure of thespring.

What is claimed is:

1. A relief valve for high pressure steam com-' prising a valve bodyhaving a discharge port therein, a cooperating valve and seat forcontrolling the discharge through the port, an elongated stein connectedto the valve, a spring -mounted on the stem at a location remote fromthe valve, an open frame having radiating fins surrounding the stemintermediate the spring and valve and having a" loose passage for thestem communicating with the valve body, and a deflector mounted upon andsurrounding the stem within the open frame and arranged to deflectoutwardly through the frame, steam escaping from the valve body aboutthe stem.

2. A relief valve for high pressure steam comprising a valve body havinga discharge port therein, a cooperating valve and seat for controllingthe discharge through the port, an elonated valve stem connected at oneend to the valve, a spring surrounding the stem at the other endthereof, an open frame between the valve and the spring having headportions loosely fitting about the valve stem and connecting membersarranged to provide openings between the head portions, a sleeveconnected at one end to the valve body and surrounding the valve at theother end thereof for guiding the valve in its movement away from thevalve seat, and a deflector within the open frame fitting the valve stemclosely to prevent contact of the steam with the spring and fordirecting it through the openings in the frame.

3. A relief valve for high pressure steam comprising a valve body havinga discharge port therein, a cooperating valve and seat for controllingthe discharge through the port, an elongated valve stem connected at oneend'to the valve, 2. spring mounted on the stem at the other endthereof, a frame between the valve and the spring having disk-shapedhead portions fitting loosely around the valve stem and a series ofnarrow fins arranged lengthwise of and spaced in angular relation aboutthe valve stem between the disk members for reducing the escape of steamaround the stem from the main valve body and for preventing contact ofthe steam with the spring, and a steam deflector fixed to the portion ofthe valve stem between the head portions of the frame for directing thesteam. which escapes between the head portion nearest the valve and thestem away from the head portion nearest the spring and through thespaces between the fins.

4. A relief valve for high pressure steam comprising a valve body havinga discharge port therein, a cooperating valve and seat for controllingthe discharge through the port, an elongated valve stem connected at oneend to the valve, a spring surrounding the stem at the other endthereof, a frame between the valve and the spring having disk-shapedhead portions fitting loosely around the valve stem and connectingmembers arranged to provide openings between the head portions andspaced from the valve stem for reducing the escape of steam around thestem from the valve body and for preventing contact of the steam withthe spring, and means movable with the valve stem operating between thehead portions of the frame for deflecting the steam passing throughthe'head por- I tion nearest the valve away from the head por- Hi tionnearest the spring and through the openings formed by the connectingmembers.

5. A relief valve for high pressure steam comprising a valve body havinga discharge port therein, a cooperating valve and seat for controllingthe discharge through the port, an elongated stem connected to thevalve, a spring mounted on the stem at a location remote from the valve,an open frame having heat radiating fins surrounding the stemintermediate the spring and valve and providing a loose passage for thestem in communication with the valve body, and means for immediatelydeflecting steam escaping outwardly from the valve body through theloose passage away from the region of the stem and outwardly between theradiating fins.

KENNETH S. M. DAVIDSON.

